In many applications it is desirable to so modulate the spatially varying intensity of an input two dimensional optical signal as to provide a two dimensional output signal defining a two valued spatially varying state distribution in conformance with the way the intensity of the input two dimensional signal is spatially distributed above or below a selectable threshold intensity. Where 2-D imaging quality is important, the modulators are further called upon to provide a high spatial resolution. The modulators should in addition be able to be fabricated at reasonably low-cost and in such a way that the resolution of the device is not subject to degradation by manufacturing and materials irregularities. Power consumption, and therewith heat radiation, should be as low as possible to enable, among other things, scalability to any intended device size. Switching speeds between states should be relatively high, so that the device can provide a high information handling rate. Sensitivity to low intensity input signal levels and high optical gains should be selectively available, and, among other things, the modulator should provide long-term and readily erasable latching, be operable at room temperatures, and be completely cascadable with other subsystems. The heretofore known devices and technologies have been deficient in one or more of the foregoing and other aspects.